#include <fstream>
#include <stack>
#define N 100001
#include <set>
using namespace std;
ifstream cin("interclasari.in");
ofstream cout("interclasari.out");
multiset <int> s;
int main()
{
    int n,k,i,j,x;
    cin >> k;
    for(i = 1;i <= k;i++){
        cin >> n;
        for(j = 1;j <= n;j++){
            cin >> x;
            s.insert(x);
        }
    }
    multiset <int> ::iterator it;
    cout << s.size() << "\n";
    for(it = s.begin();it != s.end();it++){
        cout << *it << " ";
    }
    return 0;
}